1G 1.8L dying randomly, MPI?

[Redrocketlaser]

I daily drive a 91 Laser with a 1.8 and among all the other issues one is about to drive me nuts. I will be driving down the road like normal then I will hear my MPI relay click and my tach will shoot straight to zero and my engine will die (even coasting down the road in gear after it dies the tach shows zero). Sometimes it will immediately restart and be fine other times it refuses to start from anywhere between 3-20 minutes.

This happened yesterday on my way home and I was stranded on the side of the road for about 20 minutes, trying everything I knew to do (unhook the battery and wait, hit the fuse box under the hood a few times, hit under he dash where the MPI is mounted) until it finally decided to start and let me finish my drive home. I should mention that the car has killed 2 alternators and 3 batterys in about the 2 yrs I've owned it, and the problem always seems to be a little better right after a new battery. It also happens a lot more frequently when I'm using electronics in the car (heater, wipers, lights radio etc.) Maybe the MPI is losing just enough power to shut it off?

Anyone have any experience with this?

 

[97egl]

Have you checked the ECU at all? A lot of weird issues are caused by leaking capacitors eating traces on the board

Also on a side note about the alternators, if you are getting parts store ones it is not your car that is killing them. The parts stores just sell complete garbage. If you have the original one buy a new OEM regulator assembly that will come with new brushes and install it. 95% chance it fixes the alternator and lasts another 150k miles or more

 

[steve]

Based on the symptoms the ECU would be my first bet too.
When it dies is the CEL on? When it won't restart does the CEL turn on for five seconds and then turn off?
Checking to make sure you have a solid 12 to 14 volts on your electrical system all the time is also something to check since the ECU will shutdown somewhere below 9 volts.

Dang, there was something else I was going to mention but the thought melted...

Oh, now I remember. The MPI relays are pretty solid, they can and have failed but it's not a high likelyhood item where every 1G DSM ECU (and TCU) will fail from the capacitors leaking. They started doing that from the very beginning.

 

[Redrocketlaser]

I'll have to get the ecu out and take a look.

It did it again today at the store as I was leaving, I sat for a few minutes with the neg terminal off and it still wouldn't start. Not sure if I ever mentioned it before in another thread but the car is started via push button, done by the previous owner for reasons unknown. The reason I mention this NOW is because I got the urge to just try to turn the key to start knowing it wouldn't actually start the car, and when I did I heard my mpi click and my fuel pump turn on, so I tried the push button again and it fired right up. Idk if it was just the timing or maybe something is going on with my ignition switch but I'll have to remember to try that next time it acts up.

Also the cel is always on, I've yet to figure out how to pull codes honestly either that or my attempts were correct and there's just no power to the obd port

 

[steve]

Also the cel is always on, I've yet to figure out how to pull codes honestly either that or my attempts were correct and there's just no power to the obd port

It's a little more difficult now that RadioShack is gone from every street corner but the basics remain the same.

1G - CEL LED code flasher

After helping out a member on Facebook with making this code flasher I decided to post it up on DSMtuners for anyone who needs help understanding how to make one of these to pull codes from there 1g DSM (turbo or non-turbo).TOOLS YOU WILL NEED: soldering iron (electrical, or gas heated...

www.dsmtuners.com

1G - Diagnostic testing without a scantool (CEL testing) ~ 1g Turbo models

Is your 1g throwing a check engine light? Here is a simple way to diagnose it without the use of a scantool or diagnostic checker.All you will need is a simple voltmeter. First, locate the OBD (Is right next to the fuse box near the driver's feet).You must be registered to see element. You...

www.dsmtuners.com

1G - 1g Code Reader - CEL CODE READER

This is a How-To on figuring out your Check engine light (CEL) for 1g.Tools: Volt Meter or LEDConnection: Connect the positive of the volt meter or LED to pin #1 and the ground to #12 pin on the port. You must be registered to see element.After you got that done, turn your key to the ON...

www.dsmtuners.com

The 1.8L Fault codes are slightly different than the 2.0L.

Order - Error Code

1 Engine Control Unit (No output or Solid)
2 11 Oxygen Sensor
3 12 Air Flow Sensor
4 13 Intake Air Temperature Sensor
5 14 Throttle Position Sensor
6 15 Motor Position Sensor
7 21 Engine Coolant Temperature Sensor
8 22 Crank Angle Sensor
9 23 No 1 Top dead center sensor
10 24 Vehicle Speed Sensor (Reed Switch)
11 25 Barometric Pressure Sensor
12 36 Ignition Timing Adjustment Signal
13 41 Fuel Injector
14 42 Fuel Pump
15 43 EGR (89-93 California 94 All)
16 Normal Operation (heartbeat) On/Off Repeating

 

[Redrocketlaser]

It's a little more difficult now that RadioShack is gone from every street corner but the basics remain the same.

1G - CEL LED code flasher

After helping out a member on Facebook with making this code flasher I decided to post it up on DSMtuners for anyone who needs help understanding how to make one of these to pull codes from there 1g DSM (turbo or non-turbo).TOOLS YOU WILL NEED: soldering iron (electrical, or gas heated...

www.dsmtuners.com

1G - Diagnostic testing without a scantool (CEL testing) ~ 1g Turbo models

Is your 1g throwing a check engine light? Here is a simple way to diagnose it without the use of a scantool or diagnostic checker.All you will need is a simple voltmeter. First, locate the OBD (Is right next to the fuse box near the driver's feet).You must be registered to see element. You...

www.dsmtuners.com

1G - 1g Code Reader - CEL CODE READER

This is a How-To on figuring out your Check engine light (CEL) for 1g.Tools: Volt Meter or LEDConnection: Connect the positive of the volt meter or LED to pin #1 and the ground to #12 pin on the port. You must be registered to see element.After you got that done, turn your key to the ON...

www.dsmtuners.com

The 1.8L Fault codes are slightly different than the 2.0L.

Order - Error Code

1 Engine Control Unit (No output or Solid)
2 11 Oxygen Sensor
3 12 Air Flow Sensor
4 13 Intake Air Temperature Sensor
5 14 Throttle Position Sensor
6 15 Motor Position Sensor
7 21 Engine Coolant Temperature Sensor
8 22 Crank Angle Sensor
9 23 No 1 Top dead center sensor
10 24 Vehicle Speed Sensor (Reed Switch)
11 25 Barometric Pressure Sensor
12 36 Ignition Timing Adjustment Signal
13 41 Fuel Injector
14 42 Fuel Pump
15 43 EGR (89-93 California 94 All)
16 Normal Operation (heartbeat) On/Off Repeating

Thanks for the info! Gonna have to check the codes out when I get a chance. Cel has been on since I got it and the previous owner told me it was for an 02 sensor so I've always assumed that's why, but since it's been acting up there are probably other stores codes by now.

Update! The car died on me twice this morning on the way to work and instantly restarted while rolling when I turned the key to start! So I'm assuming my ignition switch is acting up. This is great news, I've been trying for a long time to find something that will kick the mpi back on when it does this!